The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 19, 2013
Filed:
Jan. 09, 2012
Applicants:
Shigeru Maida, Joetsu, JP;
Hisatoshi Otsuka, Joetsu, JP;
Inventors:
Shigeru Maida, Joetsu, JP;
Hisatoshi Otsuka, Joetsu, JP;
Assignee:
Shin-Etsu Chemical Co., Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G03F 1/22 (2012.01); G03F 1/24 (2012.01); B32B 9/00 (2006.01);
U.S. Cl.
CPC ...
Abstract
In a titania-doped quartz glass member having a surface where EUV light of up to 70 nm wavelength is reflected, a refractive index distribution in the surface has only one extreme point within a central 80% region of the member. The titania-doped quartz glass member has a surface with a high level of precision and thus can be formed into an EUV lithography photomask substrate which is improved in flatness and thermal expansion properties.